The proteins of the wheat kernel

Abstract

IIChittenden & Smith1 prepared many samples of gluten-casein according to Ritthausen's method.As an average of eight analyses they found the following composition : p. ct.Carbon 52.87 Hydrogen 6.99 Nitrogen 15.86 Sulphur 1.17 Oxygen 23. 1 1 100.00They also prepared and analyzed the various products of peptic digestion of this protein.Osborne & Voorhees2 investigated the number and character of the proteins of wheat, but as their results are given in detail in the body of this paper they need not here be further mentioned.O'Brien* recognized globulin, proteose, and the gluten-proteins in extracts of wheat flour.The protein-leucosin, which Osborne & Voorhees considered to be an albumin, was regarded as a globulin by O'Brien, since it is precipitated by saturating its solutions with magnesium sulphate.About i per cent of the flour consists of proteins soluble in saline solutions and coagulating on boiling.Neither ferment action nor globulin take part in gluten formation.Gluten consists of zymom, insoluble in alcohol, and glian, soluble therein.Glian is formed by hydration of the protein of the flour and zymom from glian by further hydration.Glian yields myxon, glutine, and mucine, which are not constituents of glian, but derived from it.Frankfurt* estimated the proportion of various constituents of the embryo of wheat, and found globulin 21.62 per cent and albumose 13.62 per cent.O'Brien5 stated that the proteins of the wheat embryo consist of globulins of themyosin type, coagulating at 55°, soluble in dilute solutions of sodium chloride or magnesium sulphate and precipitated by excess of these salts ; globulins of the vitellin type, coagulating at 75° to 78°, and soluble in dilute solution of sodium chloride, but not precipitated by an excess ; proteose and albumin, not coagulating below 80°, soluble in sodium chloride solution, but not precipitated by an excess, nor by dialysis, nor by carbonic acid.Kjeldahl6 found that all of a number of preparations of the alcohol-soluble protein made from wheat flour showed an almost constant content of about 52 per cent of carbon and 17.25 per cent of nitrogen, and when dissolved in 1